Numerous procedures involving catheters and other minimally invasive devices may be performed to provide a wide variety of treatments, such as ablation, angioplasty, dilation or the like. For example, to treat cardiac arrhythmias, physicians often employ specialized ablation catheters to gain access into interior regions of the body. Such catheters include tip electrodes or other ablating elements used to create ablation lesions that physiologically alter the ablated tissue without removal thereof, and thereby disrupt and/or block electrical pathways through the targeted tissue. In the treatment of cardiac arrhythmias, a specific area of cardiac tissue having aberrant electrically conductive pathways, such as atrial rotors, emitting or conducting erratic electrical impulses, is initially localized. A user (e.g., a physician) directs a catheter through a vein or artery into the interior region of the heart that is to be treated. Subsequently, the ablating portion of the selected device is next placed near the targeted cardiac tissue that is to be ablated, such as a pulmonary vein ostium or atrial wall.
An ablation procedure may involve creating a series of inter-connecting lesions in order to electrically isolate tissue believed to be the source of an arrhythmia. During the course of such a procedure, a physician may employ several different catheters having variations in the geometry and/or dimensions of the ablative element in order to produce the desired ablation pattern. Multiple devices having varying dimensions and/or shapes may also be employed to account for variations in anatomical dimensions from patient to patient. Each catheter may have a unique geometry for creating a specific lesion pattern or size, with the multiple catheters being sequentially removed and replaced to create the desired multiple lesions. Exchanging these various catheters during a procedure can cause inaccuracies or movement in the placement and location of the distal tip with respect to the tissue to be ablated, and may further add to the time required to perform the desired treatment. These potential inaccuracies and extended duration of the particular procedure increase the risk to the patient undergoing treatment.
In addition, while some existing devices provide may provide for some adjustability in their geometry, the effective ability to make such adjustments may be hampered by kinking or other unwanted impediment that frustrates the ability of one or more controls on a proximal portion of a device operated by a physician to accurately translate into the desired modification at a distal portion of a device within the patient.
In light of the above, it is desirable to provide a medical device having multiple, effectively-controllable shapes or dimensions, thereby reducing or eliminating the need for additional medical devices having varied, but limited geometric orientations, and thus, limited ability to provide multiple ablative patterns or sizes.